A Taiwanese pig farmer displays a piglet during a demonstration outside health department headquarters in Taiwan.

Using antibiotics in meat causes farmers to develop drug-resistant infections known as superbugs, a new study says. The study, published in the journal mBio, looks at a strain of MRSA that causes skin infections and sepsis, the New Scientist reported. The study authors, a team lead by Paul Keim of the Translational Genomics Research Institute, were able to trace the drug-resistant infections to the common practice of putting antibiotics in livestock feed.

The scientists found that a staph germ had first passed from human farmers to pigs. The pigs then passed the germ back to the humans, this time in an antibiotic-resistant form. "It's like watching the birth of a superbug," Lance Price of the Translational Genomics Research Institute told National Public Radio.

This "pig MRSA," detected in half of all meat sampled in the United States, doesn't just pose a risk to farmers. Though most consumers can kill the bacteria if they cook the raw meat properly, the infection still appears to be spreading beyond people who work directly with livestock. "Initially we could always trace it back to livestock exposure," Price told NPR. "But now we are starting to see cases of resistant strains that we can't trace back."

Antibiotics are routinely fed to animals that are kept in confined animal feeding operations, also known as factory farms. The drugs are meant to combat the unsanitary conditions often seen in factory farms.

While the drugs reduce infections in the short-term, scientists have long said that routine use of antibiotics in meat would have dire long-term consequencies.The European Union banned the routine use of antibiotics in meat in 2006.

The National Pork Producers Council, however, continues to argue that antibiotic use in animals does not harm humans.